Fused nanostructure material

ABSTRACT

Disclosed herein is a nanostructured material comprising carbon nanotubes fused together to form a three-dimensional structure. Methods of making the nanostructured material are also disclosed. Such methods include a batch type process, as well as multi-step recycling methods or continuous single-step methods. A wide range of articles made from the nanostructured material, including fabrics, ballistic mitigation materials, structural supports, mechanical actuators, heat sink, thermal conductor, and membranes for fluid purification is also disclosed.

[0001] This application claims the benefit of domestic priority to U.S.Provisional Patent Application Ser. No. 60/474,925 filed Jun. 3, 2003,which is herein incorporated by reference in its entirety.

[0002] The present disclosure relates to a nanostructured materialcomprising carbon nanotubes fused together to form a three-dimensionalmaterial, and a method of making such a material.

[0003] Most two-dimensional materials, such as webs, sheets, and thelike, have inherent shortcomings to their material properties. Whilemetals and plastic have long been favorites because of their wide rangeof versatility, for many applications higher strength, higherconductivity, and overall higher performing materials are needed. Whilethe need for such exotic materials used to be confined to high techapplications like space exploration and electronics, they are becomingincreasingly important for mass applications in ballistic mitigationapplications (such as bulletproof vests), heat sinks, air conditioningunits, computer casings, car bodies, aircraft wings and parts, and manyother applications that cannot tolerate the high cost of current highperforming materials.

[0004] For example, one only need read the daily paper to understand theurgent requirement for a protective material for addition to lightly orunarmored military vehicles in service through out the world.Combatant's lives are being lost, virtually every day and many of theselosses are directly attributable to the explosive force of buriedmunitions, triggered by remote control, when a vehicle passes over theburied device.

[0005] Military requirements call for the creation of new light weightbody armor for combatants. New materials are sought for protection ofstructures and building from blast forces. Similarly, air transportrequires blast protection for cargo hold containers transportingfreight, or for fuselage protection transporting people.

[0006] Current armor protection materials are either unavailable due togreat demand for individual body armor, and/or are too heavy or tooexpensive for the service vehicles.

[0007] Recent advances in materials science and nanotechnology have madethe creation of a new class of materials possible; materials withstrength to weight ratios never before achieved. The carbon nanotube,discovered in the early 1990's, has been widely touted as the next majormolecule for use in a nanocomposite material. Scientists studying thematerial properties of carbon nanotubes assert that this newnanomolecular material is the strongest material known to man. Theenormous theoretical strength properties of the carbon nanotube havenot, prior to the Inventor's work, been realized.

[0008] As discussed in “SUPER-TOUGH CARBON-NANOTUBE FIBRES,” Alan B.Dalton et al, Nature, Volume 423, Page 703, 12 June 2003, NaturePublishing Company, which is herein incorporated by reference, singlewall carbon nanotube based composite have demonstrated energy of rupture20 times of that for Kevlar® based composites. Due in part to the muchstronger bonding between the nanotubes associated with the inventiveprocess, the energy of rupture of the inventive material is expected tobe greater than that previously reported.

[0009] Accordingly, creating materials, such as a cloth and compositesthat comprises ultra-strong carbon nanotubes fused together to form ahighly cross-linked network would be useful for any applicationrequiring high strength, high thermal conductivity, electricalconductivity, and other applications where carbon nanotubes have shownthemselves to be superior materials.

[0010] Accordingly, the present disclosure relates to a nanostructuredmaterial composed of fused carbon nanotubes and methods of making such amaterial. The properties associated with such a material leads to arange of beneficial properties such as ultra-high tensile strength,acceptable flexibility and good thermal conductivity and electricalconductivity.

SUMMARY OF THE INVENTION

[0011] The following disclosure describes a nanostructured materialcomprising carbon nanotubes fused together to form a three-dimensionalstructure. Nanotubes described herein generally have an average diameterin the inclusive range of from 1-60 nm and an average length in theinclusive range of from 0.1 μm to 250 mm.

[0012] As used herein the term “fused,” “fusion,” or any version of theword “fuse” is defined as the bonding of nanotubes at their point orpoints of contact. For example, such bonding can be Carbon-Carbonchemical bonding including sp³ hybridization or chemical bonding ofcarbon to other atoms.

[0013] In the most general sense, the method of making thenanostructured material described herein comprises

[0014] dispersing nanotubes in an appropriate fluid, with or withoutsurfactants, to form a nanotube aliquot,

[0015] depositing the nanotube aliquot onto a porous substrate in anamount sufficient to obtain a substantially stable interlockingmonolithic structure, and

[0016] fusing the carbon nanotubes together to form a three dimensionalnanostructure.

[0017] In one aspect, the method comprises a multi-step recycling methodof making a three-dimensional nanostructure, comprising

[0018] (1) growing carbon nanotubes in a reactor;

[0019] (2) fusing the grown nanotubes to form a three dimensionalnanostructure;

[0020] (3) performing a catalytic procedure on the three-dimensionalnanostructure;

[0021] (4) repeating (1) to (3) for a time sufficient to achieve adesired thickness or property for the three-dimensional nanostructure.

[0022] In another aspect, the method comprises a continuous method ofmaking a three-dimensional nanostructure material, the method comprisinggrowing carbon nanotubes, in situ, and fusing the grown carbon nanotubessubstantially simultaneously with the growing process.

DETAILED DESCRIPTION OF THE INVENTION

[0023] As stated, the present invention relates to a nanostructuredmaterial comprising carbon nanotubes fused together to form athree-dimensional structure. In one aspect of the present disclosure,the nanostructured material comprises defective carbon nanotubes chosenfrom impregnated (which is defined as other atoms or clusters insertedinside of nanotubes), functionalized (which is defined as bonding atomsor chemical groups to the surface of the nanotubes), doped (which isdefined as the presence of atoms, other than carbon, in the nanotubecrystal lattice), charged (which is defined as the presence ofnon-compensated electrical charge, in or on the surface of the carbonnanotubes), coated (which is defined as a nanotube surrounded by ordecorated with clusters of atoms other than carbon), and irradiated(which is defined as the bombardment of nanotubes with particles orphotons such as x-rays of energy sufficient to cause inelastic change tothe crystal lattice of the nanotube. Such nanotubes may be boundtogether or with other “support” materials. “Nanostructured” refers to astructure on a nano-scale (e.g., one billionth of a meter), such as onthe atomic or molecular level.

[0024] “Chosen from” or “selected from” as used herein refers toselection of individual components or the combination of two (or more)components. For example, the nanostructured material can comprise carbonnanotubes that are only one of impregnated, functionalized, doped,charged, coated, and irradiated nanotubes, or a mixture of any or all ofthese types of nanotubes such as a mixture of different treatmentsapplied to the nanotubes.

[0025] “Nanostructured material” is a material comprising at least oneof the above-mentioned carbon nanotube components. Defective carbonnanotubes are those that contain a lattice distortion in at least onecarbon ring. A lattice distortion means any distortion of the crystallattice of carbon nanotube atoms forming the tubular sheet structure.Non-limiting examples include any displacements of atoms because ofinelastic deformation, or presence of 5 and/or 7 member carbon rings, orchemical interaction followed by change in sp² hybridization of carbonatom bonds.

[0026] Another aspect of the invention is directed to elongatednanotubes comprising carbon, wherein the nanotube is distorted bycrystalline defects, similar to those described above. In thisembodiment, the nanotubes are distorted, due to the defects, to a degreethat the nanotubes, when treated, have significantly greater chemicalactivity that allow the nanotube to react with, or bond to, chemicalspecies that would not react with or bond to undistorted and/oruntreated nanotubes.

[0027] The carbon nanotubes used in the nanostructured material may havea scrolled tubular or non-tubular nano-structure of carbon rings, andmay be single-walled, multi-walled, nanoscrolled or combinationsthereof.

[0028] The carbon nanotubes having a scrolled tubular or non-tubularnano-structure have a morphology chosen from nanohorns, cylinders,nanospirals, dendrites, spider nanotube structures, Y-junctionnanotubes, and bamboo morphology.

[0029] The above described shapes are more particularly defined in M. S.Dresselhaus, G. Dresselhaus, and P. Avouris, eds. Carbon Nanotubes:Synthesis, Structure, Properties, and Applications, Topics in AppliedPhysics. Vol. 80. 2000, Springer-Verlag; and “A Chemical Route to CarbonNanoscrolls, Lisa M. Viculis, Julia J. Mack, and Richard B. Kaner;Science 28 Feb. 2003; 299, both of which are herein incorporated byreference.

[0030] In certain embodiments, the three-dimensional nanostructuredmaterial may further comprise at least one material chosen frompolymers, ceramics, and metals, which may be in a form chosen fromfibers, beads, particles, wires, sheets, foils, and combinationsthereof.

[0031] These materials may be used to support the fabrication of thethree-dimensional structure and may become an integral part of thestructure. Alternatively, these materials may be sacrificial, meaningthat they are removed by subsequent processing, such as a thermal orchemical procedures, to eliminate them from the final structure, whileleaving a stable structure comprised almost entirely of carbonnanotubes. The sacrificial support material is generally used inapplications that do not require the properties of the support material,such as in certain high strength or armor/ballistic applications.

[0032] Non-limiting examples of polymers that can be used in thenanostructured material described herein are chosen from single ormulti-component polymers including nylon, polyurethane, acrylic,methacrylic, polycarbonate, epoxy, silicone rubbers, natural rubbers,synthetic rubbers, vulcanized rubbers, polystyrene, aramid,polyethylene, ultra-high-molecular weight polyethylene, high-densitypolyethylene (HDPE), low-density polyethylene (LDPE),poly(p-fenyl-2,6-benzobisoxazol), polypropylene, polychloroprene,polyimide, polyamide, polyacrylonitrile, polyhydroaminoester, polyester(polyethylene terephthalate), polybutylene terephthalate,poly-paraphylene terephtalamide, polyester ester ketene, vitonfluoroelastomer, polytetrafluoroethylene, and polyvinylchloride.

[0033] Non-limiting examples of ceramics that can be used in thenanostructured material described herein include: boron carbide, boronnitride, boron oxide, boron phosphate, beryllium oxide, spinel, garnet,lanthanum fluoride, calcium fluoride, silicon carbide, carbon and itsallotropes, silicon oxide, glass, quartz, aluminum oxide, aluminumnitride, zirconium oxide, zirconium carbide, zirconium boride, zirconiumnitrite, hafnium boride, thorium oxide, yttrium oxide, magnesium oxide,phosphorus oxide, cordierite, mullite, silicon nitride, ferrite,sapphire, steatite, titanium carbide, titanium nitride, titanium boride,and combinations thereof.

[0034] Non-limiting examples of metals that can be used in thenanostructured material described herein include aluminum, boron,copper, cobalt, gold, platinum, silicon, steel, titanium, rhodium,indium, iron, palladium, germanium, tin, lead, tungsten, niobium,molybdenum, nickel, silver, zirconium, yttrium, and alloys thereof.

[0035] In one embodiment, at least one of the previously describedpolymers, ceramics, and metals are coated on the surface of the carbonnanotubes to form a polymer containing layer, a ceramic containinglayer, a metal containing layer, or a combination of any or all of theselayers. For example, in certain ballistic applications thenanostructured material may comprise at least one layer of boroncarbide.

[0036] During the processing of the nanostructured material of oneaspect of the invention, the resulting structure may comprise 5, 6 and7-membered carbon rings at the intersection of two or more carbonnanotubes. These different ring structure can lead to distortions in thecarbon nanotubes, which tend to aid in the formation of aself-assembling nanostructured material

[0037] The ability of the nanostructured material to have a awide-ranging density, for example ranging from 1 picogram/cm³ to 20g/cm³, such as 1.25 g/cm³, allows the material to be tailored for avariety of applications. Non-limiting examples of articles made from thenanostructured material described herein range from fabrics tostructural supports. Electrical, mechanical and thermal propertiesassociated with the carbon nanotube further allow the nanostructuredmaterials to be used in mechanical actuators, heat sink, thermalconductor, or membranes for fluid purification.

[0038] For example, because of the high thermal transfer of carbonnanotubes, e.g., about thirty times the thermal conduction of copper,thermal conductors may be used. Alternatively, the insulating propertiesassociated with this material enables blankets, tents, sleeping bags,clothes, and building materials to be constructed from the materialdescribed herein. The material can be functionalized to be an insulatorby keeping nanotube ends from direct connection. The phonons can notpropagate with in the material. Alternatively, by connecting the endsexcellent thermal transport is achieved. For example, nanotubes canexhibit up to twice the heat conduction of atomically perfect diamond.

[0039] Carbon nanotubes, which are typically 7-10,000 times moreelectrically conductive than copper, enable materials described hereinto be used in conducting or near super-conducting applications.

[0040] In addition, the high strength associated with carbon nanotubes,about 100 times the tensile strength of steel at {fraction (1/6)}th theweight, allows the nanostructured material described herein to be madeinto puncture resistance applications, such as projectile bombardment orother ballistic mitigation applications. In particular, thenanostructured material described herein exhibits excellent blastmitigation properties, which may be defined in terms of energy adsorbedper unit impact area as a function of the mass of the affected compositematerial.

[0041] In such ballistic mitigation applications, the nanostructuredmaterial can primarily comprise carbon nanotubes in a compositioncontaining boron carbide. Alternatively, the nanostructured material cancomprise at least one layer of carbon nanotubes and at least onematerial, such as in an alternating layer configuration with the carbonnanotube layer, chosen from the previously described polymers, ceramics,and metals fused together to form a three-dimensional structure.

[0042] For example, boron carbide is a traditional ceramic generallyused for blast mitigation materials. The primary drawback of thismaterial is that it is brittle. However, by incorporating boron into theouter shells of a multiwalled carbon nanotubes, it is possible toproduce a material that will have the flexibility and strengthcharacteristics of carbon nanotubes and the micro hardness of boroncarbide.

[0043] To simply incorporate boron into carbon nanotube material in thenative form of powder generally yields non-uniformities. To avoid thisproblem, the Inventors have found it to be advantageous to treat thenanotubes after they have been formed into a nanostructured materialwith boron carbide to develop a coated or doped nanotubes and saidmaterial having a controlled density and porosity.

[0044] The boron treatment can be performed by a variety of methods. Forexample, Chemical Vapor Deposition (CVD) can be used to grow a boroncarbide layer surrounding the carbon nanotubes. Alternatively, a hybridmethod that uses CVD to deposit boron on the carbon nanotube while thematerial is irradiated with an electron beam in a range from 80 keV to1.4 MeV can also be used. In this process, the electron beam providessufficient energy to react the carbon in the outer walls of the nanotubewith the boron to produce boron carbide. Other methods to treat carbonnanotubes with boron carbide include, but are not limited to plasmaspray coating and magnetron sputtering.

[0045] In general ballistic cloth is a material in a shape of a cloththat will protect personal or equipment from projectile impact. Forexample, a flexible cloth that can be worn by personnel in a hostileenvironment. Using one of the methods described herein, a ballisticcloth may be made in which carbon nanotubes and at least one materialchosen from the previously described polymers, ceramics, and metals, arepresent in an amount sufficient to mitigate blast forces fromprojectiles or explosives coming into contact with the ballistic cloth.This type of material may comprise a component of body armor, vehiclearmor, bullet-proof vests, shields, blankets, tents, sleeping bags,cargo containers, shipping containers, storage boxes and containers,building shielding materials, and structural components of vehicles,aircraft, spacecraft, and train cars.

[0046] More generally, a fabric made from or comprising thenanostructured material described herein may comprise a garment orarticle of clothing to be worn or to cover a person or animal, or tocover a vehicle, aircraft, spacecraft, train car, or generally anyequipment or structure which may benefit from the mechanical,electrical, and/or thermal properties associated with the carbonnanotube.

[0047] Also described herein are methods of making a three-dimensionalnanostructure. In one embodiment, the method comprises dispersingnanotubes in an appropriate fluid, with or without surfactants, to forma nanotube aliquot,

[0048] depositing the nanotube aliquot onto a porous substrate in anamount sufficient to obtain a substantially stable interlockingmonolithic structure, and

[0049] fusing the carbon nanotubes together to form a three dimensionalnanostructure.

[0050] As used herein “dispersing” comprises ultrasonication ormechanical mixing in a blender. An appropriate fluid for dispersingnanotubes may comprise water, organic solvents, acids, or bases.Non-limiting examples of appropriate organic solvents include ethanol,isopropanol, methanol, and xylene.

[0051] As used herein “surfactant” comprises a molecule with two ends:one hydrophobic end and one hydrophilic end. The surfactant enables thenanotubes to disperse in water. A non-limiting example of such asurfactant that can be used in the method described herein is SDS(sodium dodecylsulfate)

[0052] In another embodiment, the nanotube aliquot further comprises asupport material chosen from the previously described polymers,ceramics, and metals, which may be in a form chosen fibers, beads,particles, wires, sheets, foils, and combinations thereof, and beingdispersed with the carbon nanotubes.

[0053] When a support material is used, dispersing generally comprisesultrasonication at a level sufficient to cause ultrasonic bonding of thesupport material alone or with the carbon nanotubes. As stated, thesesupport materials may comprise an integral part of the nanostructuredmaterial, or may be sacrificial.

[0054] In addition, fusing is typically performed by irradiative,electrical, chemical, thermal, or mechanical processing, eitherindependently or in conjunction with one another. For example,irradiative processing may comprise e-beam irradiation, UV radiation,X-ray, and ionizing radiation. Chemical processing may comprise treatingthe carbon nanotubes with at least one material chosen from acids,bases, carboxyls, peroxides, and amines for a time sufficient tofacilitate fusion of the carbon nanotubes with one another. Similarly,chemical processing may comprise photochemical bonding for a timesufficient to obtain chemical cross linking. As used herein, “crosslinking” means that a chemical bond is formed between two or morenanotubes within the carbon nanotube nanostructured material.

[0055] In one embodiment, fusing comprises heating the nanostructure inan oven at a temperature below the melting point of the supportmaterial. This process can be performed in vacuum, or in an atmospherechosen from inert gases or air.

[0056] In one non-limiting embodiment, the method further comprises thechemical pr physical vapor deposition of at least one material chosenfrom previously described ceramics, metals, and polymers. During thismethod, deposition comprises the depositing of at least one of thepreviously described polymers, ceramics, and metals near theintersecting points of carbon nanotubes.

[0057] When fusing occurs through a mechanical process, it can be donethrough a method chosen from hydraulic pressing, three roll pressing,mechanical grinding. According to a method described herein, thethree-dimensional nanostructured material may be thermally orelectrically annealed to add further benefits to the structure, such asstructural integrity. For example, by passing a current through or bycreating eddy currents through electromagnetic field emersion one cancause electro migration in an amount sufficient to fuse nanotubestogether, which, depending on the particular conditions (e.g., fieldstrength, nanotube morphology, etc.) can lead not only to themodification of such defects, but can cause defect creation, eliminationor migration.

[0058] In addition to the above described method, a multi-step recyclingmethod may be used to make a three-dimensional nanostructure. Such amethod comprises

[0059] (1) growing carbon nanotubes in a reactor;

[0060] (2) fusing the grown nanotubes to form a three dimensionalnanostructure;

[0061] (3) deposition of a catalyst and growth of nanotubes on or withinthe three-dimensional nanostructure;

[0062] (4) repeating (2) to (3) for a time sufficient to achieve adesired thickness, density or property for the three-dimensionalnanostructure.

[0063] In this type of method, growing of the carbon nanotubes comprisesa catalytic CVD process. The process to grow carbon nanotubes typicallyrequires carbon containing vapor to be in presence of catalystnanoparticles at a temperature sufficient to produce carbon nanotubes.

[0064] The method of applying the catalyst in (3) comprises the ChemicalVapor Deposition or Physical Vapor Deposition of catalyst.

[0065] The process of applying the catalyst may comprise depositing ametal-organic catalyst layer, such as ferrocene or an iron pentacarbonylcontaining layer.

[0066] In addition to the previously described multi-step recyclingmethod, a continuous method of making a three-dimensional nanostructurematerial, may be used. This type of method comprises growing carbonnanotubes, in situ, and fusing the grown carbon nanotubes substantiallysimultaneously with the growing process. In one embodiment, annealingmay also be performed simultaneous with or prior to fusing. As before,annealing may be performed using a thermal or electrical process.

[0067] In any of the previously described methods, the carbon nanotubesmay be grown with a gas chosen from but not limited to: ethanol, carbonmonoxide, xylene, acetylene, and methane. Growth of the carbon nanotubesmay be enhanced/improved by depositing a metal-organic catalyst layer,such as ferrocene or iron pentacarbonyl.

[0068] Non-limiting examples of the methods used to the manufacture thenanostructure materials described herein include an organic solventevaporation process, a geometric weave process, a vacuum filtrationprocess, and a nanostructure polymerization process. Each of theseprocesses, including those described in more detail below, can create ananostructure with nanomaterials embedded on them or composed of them.

[0069] To enhance its structural support and binding to other entities,the entire nanostructured material can be coated with the previouslymentioned metals, plastics, or ceramics. In addition, structuralintegrity of the nanostrutured material can be enhance by chemical,electrical, thermal, or mechanical treatment or any combination thereof. In non-limiting embodiments, mechanical treatment could involverolling the material under pressure, electrical treatment could beperformed for a time sufficient to perform electro migration, andthermal treatment could be performed for a time sufficient to reachdiffusion bonding).

[0070] In any of the above-described methods, the starting carbonnanotubes generally contain residual iron particles or other catalyticparticles that remain after production of the nanotubes. In certainembodiments, it is desired to wash the carbon nanotubes with a strongoxidizing agent such as acids and/or peroxides or combinations there ofbefore forming a nanostructured material. Upon washing with a strongoxidizing agent, the iron generally found in the carbon nanotubes isoxidized to Fe++ and Fe+++. In addition, acid washing has the benefit ofremoving amorphous carbon which interferes with the surface chemistry ofthe nanotube.

[0071] It is also thought that this acid washing procedure contributesto the high degree of hydrophilicity of these functionalized carbonnanotubes and the resulting carbon nanostructured material. The washedcarbon nanotubes are generally fabricated into a nanostructured materialusing one of the following processes. It is noted that any one of thefollowing processes, as well as those described in the followingsections, can be used to create a nanostructured material describedherein, whether multi or monolayered.

[0072] Organic Solvent Evaporation Process

[0073] In the Organic Solvent Evaporation Process, a nanostructurematerial, such as a fluid sterilization membrane, can be made by bondingnanomaterials with an adhesive. Examples of fluid sterilizationmembranes that can be made in accordance with method described hereincan be found in co-pending U.S. patent application Ser. No. 10/794,056,filed Mar. 8, 2004, which is herein incorporated by reference. Examplesof adhesives are chemical adhesives, such as glue.

[0074] According to this process, carbon nanotubes can be mixed with aorganic solvent, such as methanol, ethanol, isopropanol or xylene. Inone embodiment, this dispersion is next placed in an ultrasonic bath fora time sufficient to exfoliate the carbon nanotubes. The resultingdispersion is next poured onto porous substrate to remove organicsolvent. Additionally, other polymers or polymeric materials may beadded to the organic solvent to enhance the resulting said nanostruturedmaterials physical or mechanical properties.

[0075] Deposition Process

[0076] In this process, a nanostructured material can be made by vacuumdeposition of carbon nanotube dispersions to lay down layers of carbonnanotubes on at least one substrate. Ultrasonication using a “Branson900B” Model at 80% to 100% power may be used to aid in dispersing and/ordeagglomerating carbon nanotubes during deposition.

[0077] An envisioned process of the deposition method comprises placingcarbon nanotubes in a suitable organic solvent or water andultrasonicating using a “Branson 900B” Model at 80% to 100% power for atime sufficient to disperse the carbon nanotubes during deposition. Thesolution can be placed in a vacuum filtration device equipped withultrasonication to further ensure that the carbon nanotubes aredeagglomerated.

[0078] Fabrication of one Boron Carbide Nanostructure Material

[0079] In one embodiment, blast mitigation materials comprising thenanostructured material described herein and boron carbide can befabricated. For example, a multilayer ballistic material can be made byfirst starting with multi-walled carbon nanotubes up to 1000 microns inlength and 50 nm in width. As used in this embodiment, “multi-walled”means up to 25 walls. This morphology of carbon nanotube can be mixed ina 1:1 ratio with a sacrificial material, such a calcium oxide supportfibers 1 mm in length and 100 nm in width.

[0080] Different boron sources, such as boron carbonyl or diborane, maybe used to coat the carbon nanotube/calcium oxide mixture using achemical vapor deposition (CVD) process. For example, when boroncarbonyl is used, a CVD temperature ranging from 600° C. to 750° C.,such as 700° C. can be used. Once the nanotubes have been coated withboron then the boron carbide can be formed by raising the temperature to1100° C. When diborane is used, a higher CVD temperature, such as oneranging from 900° C. to 1200° C., such as 1100° C. can be used. Ineither case, a CVD pressure of 100 mT is generally sufficient to treatthe carbon nanotubes and develop the desired boron carbide coating.

[0081] Other methods of deposition boron to form a boron carbide layerincludes physical vapor deposition (PVD) or boron implantation,typically at 120 keV to 1.4 MeV (100 to 1,000 atoms per squarenanometer). Ion implantation is generally used when surface implantationis desired.

[0082] When relevant, crosslinking of the nanostructured material cantake place via electrical, chemical or thermal processing. For example,an e-beam process can be used to generate an energy flux of 130 keV (10particles/nanometer), which should be sufficient for crosslinking thenanostructured material.

[0083] Any of the above process can be used in either a batch orcontinuous method of making a boron carbide/carbon nanotubenanostructured material. When used in a continuous process, it isenvisioned that the speed of production can approach or even exceed theindustry standard of 100 feet per minute.

[0084] Additional general variables that may be used to fabricate aboron carbide nanostructured material described herein is shown in thefollowing table. TABLE 1 Variables Used in Nanostructured FabricationMethod Method Element Range Choices Choice Variable Low High StartingMorphology of Length  1 um 1000 km Material carbon fibers Width (nW) 10nm  10 um # of walls 10 1000 Choice and Composition Ceramic Metalmorphology of Length 10 um 100 m support fibers Width sW sW = 2x(nW) sW= 10x(nW) Sacrificial Yes/No Ratio of cnt to support Cnt:support 100:11:100 CVD Temperature Pure Boron Vapor 1900° C. 2500° C. Boron Carbonyl 600° C.  750° C. Diborane  900° C. 1200° C. CVD Pressure Boron Carbonyl1 mT 600 mT (*) Diborane 1 mT 600 mT (*) CVD Exposure time Diborane 10min 1 hr Boron Carbonyl 10 min 1 hr PVD Deposition Deposition layer 1atomic 5,000,000 atomic thickness Layers Layers TemperatureNanostructured 25° C. 500° C. Material temperature Boron ImplantationEnergy-Flux 80 keV-1fx 200 keV-1000fx Process Batch Size of batch 1(mm)³ 100 (m)³ Choices Continuous Reel Speed of 0.01 f/m 1000 f/m toReel production Crosslinking Linear E-Beam Energy-flux 0.01 f/m 1000 f/m

[0085] Other embodiments of the invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

[0086] Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, and so forth used in the specificationand claims are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by the present invention.

What is claimed is:
 1. A nanostructured material comprising carbonnanotubes fused together to form a three-dimensional structure.
 2. Thenanostructured material of claim 1, wherein said carbon nanotubes have ascrolled tubular or non-tubular nano-structure of carbon rings.
 3. Thenanostructured material of claim 2, wherein said carbon nanotubes havinga scrolled tubular or non-tubular nano-structure of carbon rings aresingle-walled, multi-walled, nanoscrolled or combinations thereof. 4.The nanostructured material of claim 2, wherein said carbon nanotubeshaving a scrolled tubular or non-tubular nano-structure have amorphology chosen from nanohorns, cylinders, nanospirals, dendrites,spider nanotube structures, Y-junction nanotubes, and bamboo morphology.5. The nanostructured material of claim 1, wherein said carbon nanotubescomprise impregnated, functionalized, irradiated, doped, charged,coated, and bonded to one another or bound with other materials, andcombinations thereof.
 6. The nanostructured material of claim 1, whereinsaid three-dimensional structure further comprises at least one materialchosen from polymers, ceramics, and metals.
 7. The nanostructuredmaterial of claim 6, wherein said polymers, ceramics, and metals are ina form chosen from fibers, beads, particles, wires, sheets, foils, andcombinations thereof.
 8. The nanostructured material of claim 6, whereinsaid polymers are chosen from single or multi-component polymers.
 9. Thenanostructured material of claim 8, wherein said single ormulti-component polymers are chosen from nylon, polyurethane, acrylic,methacrylic, polycarbonate, epoxy, silicone rubbers, natural rubbers,synthetic rubbers, vulcanized rubbers, polystyrene, aramid,polyethylene, ultra-high-molecular weight polyethylene, high-densitypolyethylene (HDPE), low-density polyethylene (LDPE),poly(p-fenyl-2,6-benzobisoxazol), polypropylene, polychloroprene,polyimide, polyamide, polyacrylonitrile, polyhydroaminoester, polyester(polyethylene terephthalate), polybutylene terephthalate,poly-paraphylene terephtalamide, polyester ester ketene, vitonfluoroelastomer, polytetrafluoroethylene, and polyvinylchloride.
 10. Thenanostructured material of claim 6, wherein said ceramics are chosenfrom at least one of the following: boron carbide, boron nitride, boronoxide, boron phosphate, beryllium oxide, spinel, garnet, lanthanumfluoride, calcium fluoride, silicon carbide, carbon and its allotropes,silicon oxide, glass, quartz, aluminum oxide, aluminum nitride,zirconium oxide, zirconium carbide, zirconium boride, zirconium nitrite,hafnium boride, thorium oxide, yttrium oxide, magnesium oxide,phosphorus oxide, cordierite, mullite, silicon nitride, ferrite,sapphire, steatite, titanium carbide, titanium nitride, titanium boride,and combinations thereof.
 11. The nanostructured material of claim 6,wherein said metals are chosen from at least one of the following:aluminum, boron, copper, cobalt, gold, platinum, silicon, steel,titanium, rhodium, indium, iron, palladium, germanium, tin, lead,tungsten, niobium, molybdenum, nickel, silver, zirconium, yttrium, andalloys thereof.
 12. The nanostructured material of claim 6, wherein atleast one of said polymers, ceramics, and metals are grown, deposited,and/or implanted on the surface or in the interior of the carbonnanotubes to form polymer containing particles or layers, ceramiccontaining particles or layers, metal containing particles or layers, ora combination of any or all of these particles or layers.
 13. Thenanostructured material of claim 12, wherein said at least one ceramiccontaining layers or particles comprise boron carbide.
 14. Thenanostructured material of claim 1, wherein said material comprises 5, 6and 7-membered carbon rings at the intersection of two or more carbonnanotubes.
 15. The nanostructured material of claim 1, wherein saidstructure has a density ranging from 1 picogram/cm³ to 20 g/cm³.
 16. Anarticle comprising the nanostructured material of claim
 1. 17. Thearticle of claim 16, which is in the form of a fabric, ballisticmaterial, structural support, mechanical actuator, heat sink, thermalconductor or insulator, or a membrane for fluid purification.
 18. Thearticle of claim 17, wherein said thermal insulator comprises a blanket,tent, clothing, or sleeping bag.
 19. A ballistic cloth comprising ananostructured material comprising carbon nanotubes and at least onematerial chosen from a polymer, ceramic, and metal fused together toform a three-dimensional structure.
 20. A multilayer ballistic clothcomprising nanostructured material comprising at least one layer ofcarbon nanotubes and at least one layer of a material chosen from apolymer, ceramic, and metal fused together to form a laminatedthree-dimensional structure.
 21. The ballistic cloth of claim 19,wherein said carbon nanotubes and said at least one material are presentin an amount sufficient to mitigate blast forces from ballistics orexplosives coming into contact with said ballistic cloth.
 22. Themultilayer ballistic cloth of claim 20, wherein said ballistic clothcomprises a component of body armor, vehicle armor, bullet-proof vests,shields, blankets, tents, sleeping bags, cargo hold containers, shippingcontainers, storage boxes and containers, building shielding materials,and structural components of vehicles, aircraft, spacecraft, and traincars.
 23. The article of claim 17, wherein said fabric comprises agarment or article of clothing to be worn or to cover a person, animal,vehicle, aircraft, spacecraft, train car, equipment, or structures. 24.A method of making a three-dimensional nanostructure, said methodcomprising dispersing nanotubes in an appropriate fluid, with or withoutsurfactants, to form a nanotube aliquot, depositing said nanotubealiquot onto a porous substrate in an amount sufficient to obtain asubstantially stable interlocking monolithic structure, and fusing saidcarbon nanotubes together to form a three dimensional nanostructure. 25.The method of claim 24, wherein said dispersing comprisesultrasonication, mechanical mixing in a blender, or combinationsthereof.
 26. The method of claim 24, wherein said nanotube aliquotfurther comprises a support material chosen from polymers, ceramics, andmetals, said support material being in a form chosen fibers, beads,particles, wires, sheets, foils, and combinations thereof, and beingdispersed with said carbon nanotubes.
 27. The method of claim 26,wherein said polymers are chosen from single or multi-componentpolymers.
 28. The method of claim 27, wherein said single ormulti-component polymers are chosen from nylon, polyurethane, acrylic,methacrylic, polycarbonate, epoxy, silicone rubbers, natural rubbers,synthetic rubbers, vulcanized rubbers, polystyrene, aramid,polyethylene, ultra-high-molecular weight polyethylene, high-densitypolyethylene (HDPE), low-density polyethylene (LDPE),poly(p-fenyl-2,6-benzobisoxazol), polypropylene, polychloroprene,polyimide, polyamide, polyacrylonitrile, polyhydroaminoester, polyester(polyethylene terephthalate), polybutylene terephthalate,poly-paraphylene terephtalamide, polyester ester ketene, vitonfluoroelastomer, polytetrafluoroethylene, and polyvinylchloride.
 29. Themethod of claim 26, wherein said ceramics are chosen from at least oneof the following: boron carbide, boron nitride, boron oxide, boronphosphate, beryllium oxide, spinel, garnet, lanthanum fluoride, calciumfluoride, silicon carbide, carbon and its allotropes, silicon oxide,glass, quartz, aluminum oxide, aluminum nitride, zirconium oxide,zirconium carbide, zirconium boride, zirconium nitrite, hafnium boride,thorium oxide, yttrium oxide, magnesium oxide, phosphorus oxide,cordierite, mullite, silicon nitride, ferrite, sapphire, steatite,titanium carbide, titanium nitride, titanium boride, and combinationsthereof.
 30. The method of claim 26, wherein said metals are chosen fromat least one of the following: aluminum, boron, copper, cobalt, gold,platinum, silicon, steel, titanium, rhodium, indium, iron, palladium,germanium, tin, lead, tungsten, niobium, molybdenum, nickel, silver,zirconium, yttrium, and alloys thereof.
 31. The method of claim 26,wherein said dispersing comprises ultrasonication at a level sufficientto cause ultrasonic binding of the support material alone or with thecarbon nanotubes.
 32. The method of claim 24, wherein said appropriatefluid comprises water, organic solvents, acids, or bases.
 33. The methodof claim 32, wherein said organic solvents comprise ethanol,isopropanol, methanol, or xylene.
 34. The method of claim 24, whereinsaid fusing is performed by irradiative, electrical, chemical, thermal,or mechanical processing, either independently or in conjunction withone another.
 35. The method of claim 34, wherein said irradiativeprocessing comprises E-beam irradiation, Ultra Violet radiation, X-ray,Plasma, or other ionizing radiation.
 36. The method of claim 34, whereinsaid chemical processing comprises treating the carbon nanotubes with atleast one chemical chosen from acids, bases, carboxyls, peroxides, andamines for a time sufficient to facilitate fusion of said carbonnanotubes with one another.
 37. The method of claim 34, wherein saidchemical processing comprises photochemical bonding for a timesufficient to obtain chemical cross linking.
 38. The method of claim 34,wherein said thermal processing comprises heating the nanostructure inan oven at a temperature below the melting point of the supportmaterial.
 39. The method of claim 38, wherein heating is performed invacuum, or in an atmosphere chosen from inert gases or air.
 40. Themethod of claim 24, further comprising chemical or physical vapordeposition of at least one material chosen from ceramics, metals, andpolymers.
 41. The method of claim 40, wherein said polymers are chosenfrom single or multi-component polymers.
 42. The method of claim 41,wherein said single or multi-component polymers are chosen from nylon,polyurethane, acrylic, methacrylic, polycarbonate, epoxy, siliconerubbers, natural rubbers, synthetic rubbers, vulcanized rubbers,polystyrene, aramid, polyethylene, ultra-high-molecular weightpolyethylene, high-density polyethylene (HDPE), low-density polyethylene(LDPE), poly(p-fenyl-2,6-benzobisoxazol), polypropylene,polychloroprene, polyimide, polyamide, polyacrylonitrile,polyhydroaminoester, polyester (polyethylene terephthalate),polybutylene terephthalate, poly-paraphylene terephtalamide, polyesterester ketene, viton fluoroelastomer, polytetrafluoroethylene, andpolyvinylchloride.
 43. The method of claim 40, wherein said ceramics arechosen from at least one of the following: boron carbide, boron nitride,boron oxide, boron phosphate, beryllium oxide, spinel, garnet, lanthanumfluoride, calcium fluoride, silicon carbide, carbon and its allotropes,silicon oxide, glass, quartz, aluminum oxide, aluminum nitride,zirconium oxide, zirconium carbide, zirconium boride, zirconium nitrite,hafnium boride, thorium oxide, yttrium oxide, magnesium oxide,phosphorus oxide, cordierite, mullite, silicon nitride, ferrite,sapphire, steatite, titanium carbide, titanium nitride, titanium boride,and combinations thereof.
 44. The method of claim 40, wherein saidmetals are chosen from at least one of the following: aluminum, boron,copper, cobalt, gold, platinum, silicon, steel, titanium, rhodium,indium, iron, palladium, germanium, tin, lead, tungsten, niobium,molybdenum, nickel, silver, zirconium, yttrium, and alloys thereof. 45.The method of claim 40, wherein said deposition comprises the depositingof at least material chosen from polymers, ceramic, and metals near theintersecting points of carbon nanotubes.
 46. The method of claim 34,wherein said mechanical processing comprises at least one method chosenfrom hydraulic pressing, three roll pressing, mechanical grinding. 47.The method of claim 24, further comprising annealing thethree-dimensional nanostructured material.
 48. The method of claim 24,further comprising a process from removing non-connected or non-fusedcarbon nanotubes from the nanostructured material.
 49. The method ofclaim 48, wherein said method said method of removing non-connected ornon-fused carbon nanotubes from the nanostructured material compriseselectric annealing.
 50. A multi-step recycling method of making athree-dimensional nanostructure, said method comprising (1) growingcarbon nanotubes in a reactor; (2) fusing the grown nanotubes to form athree dimensional nanostructure; (3) applying a catalyst and growingnanotubes on or within the three-dimensional nanostructure; (4)repeating (2) to (3) for a time sufficient to achieve a desiredthickness or property for said three-dimensional nanostructure.
 51. Themethod of claim 50, wherein said growing comprises a catalytic CVDprocess.
 52. The method of claim 51, wherein said applying the catalystin (3) comprises Chemical Vapor Deposition or Physical Vapor Depositionof catalyst,
 53. The method of claim 52, wherein applying the catalystcomprising depositing metal-organic catalyst particles.
 54. The methodof claim 53, wherein the metal-organic catalyst chosen from ferroceneand iron pentacarbonyl.
 55. A continuous method of making athree-dimensional nanostructure material, said method comprising growingcarbon nanotubes, in situ, and fusing said grown carbon nanotubessubstantially simultaneously with said growing process.
 56. The methodof claim 55, further comprising annealing, which is performedsimultaneous with or prior to said fusing.
 57. The method of claim 56wherein annealing is performed using a thermal or electrical process.58. The method of claim 55, wherein the carbon nanotubes are grown witha gas chosen from ethanol, carbon monoxide, xylene, acetylene, andmethane.